The present invention relates to discharge lamp operating apparatuses, self-ballasted discharge lamps, dimmers and illumination kits for dimming. In particular, the present invention relates to operating apparatuses that dim fluorescent lamps, for example, with a dimmer for incandescent lamps.
Fluorescent lamps are characterized by high efficiency and long life, compared with incandescent lamps, so that they are widely used. In particular, a self-ballasted fluorescent lamp in which a fluorescent lamp and a ballast circuit are integrally formed can be mounted on a socket for an incandescent lamp without any modification, so that the need for self-ballasted fluorescent lamps is increasing in view of energy saving and resources saving.
In recent years, there is an increasing demand for self-ballasted fluorescent lamps that can be dimmed with a dimmer for an incandescent fluorescent lamp as in incandescent lamps, so that dimmable self-ballasted fluorescent lamps are under development. To dim an incandescent lamp, a method generally used is as follows. A commercial power source is turned on and off with a dimmer, and an AC voltage that is phase-controlled in such a manner that the ON period is changed is input thereto. On the other hand, to dim a self ballasted fluorescent lamp, a ballast circuit to which a phase-controlled AC voltage is input and that allows dimming and operation is required.
An example of the discharge lamp operating apparatus to which a phase-controlled AC voltage is input and that dims and operates a fluorescent lamp is one disclosed in Japanese Laid-Open Patent Publication No. 11-111486. The discharge lamp operating apparatus disclosed in the publication changes the brightness of the fluorescent lamp in accordance with the conduction period (ON period) of an input phase-controlled AC voltage. FIG. 9 shows the configuration of this discharge lamp operating apparatus.
The discharge lamp operating apparatus shown in FIG. 9 includes a phase control device 102 connected to a commercial power source 101, a high frequency generating device 103, and a fluorescent lamp 108, and further includes detecting means 109 for detecting a conduction angle of a phase-controlled voltage from the phase control device 102 and photodetecting means 110 for detecting an optical output of the fluorescent lamp 108. The high frequency generating device 103 includes a high frequency blocking filter 104, a rectifying device 105, a smoothing DC voltage converter 106, and inverter portion 107. The inverter portion 107 includes a switching portion 171 and a transmission control portion 172 of the switching portion 171. The detecting means 109 changes the output frequency of the transmission control portion 172 of the inverter portion 107 in accordance with the detected conduction angle. On the other hand, the photodetecting means 110 changes the output frequency of the transmission control portion 172 in accordance with the detected output.
For dimming and operation of a dimmable fluorescent lamp, a commercially available dimmer for an incandescent lamp is often used as the phase control device 102. Although in principle, any commercially available dimmers should perform a dimming operation stably, the operation tests conducted by the inventors of the present invention confirmed that operational malfunction occurred in some cases. For example, when an operation of turning on, then turning off, and then turning off is performed with a dimmer, some dimmers are operated successfully, but other dimmers fail to turn on again and stay off. Such malfunction does not generally occur in dimming of incandescent lamps and thus it becomes one factor that prevents dimmable fluorescent from becoming popular.
Therefore, with the foregoing in mind, it is a main object of the present invention to provide a discharge lamp operating apparatus that can achieve a stable dimming operation from full light state to light-off state.
A discharge lamp operating apparatus of the present invention includes a discharge lamp; a dimmer for performing phase-control with respect to an input power source; and a ballast circuit for dimming and operating the discharge lamp in accordance with an AC voltage that is phase-controlled by the dimmer. A relationship
Z2xe2x89xa6(Vin/Vobxe2x88x921)xc3x97Z1
is satisfied, where Z1 (xcexa9) is an impedance between an input terminal and an output terminal of the dimmer, Vob (V) is a breakover voltage of a bidirectional trigger diode that applies a trigger signal and is connected to a gate terminal of a switching element included in the dimmer, Vin (V) is an effective voltage of a commercial power source, and Z2 (xcexa9) is an input impedance between the input terminals of the ballast circuit.
It is preferable that the upper limit of the Z2 (xcexa9) is 54 Kxcexa9.
It is preferable that the upper limit of the Z2 (xcexa9) is 26 Kxcexa9.
In one embodiment, a first capacitor is connected between the input terminals of the ballast circuit, and the first capacitor has a function of setting a value of the Z2 (xcexa9).
In one embodiment, a series circuit including a second capacitor and a resistor is connected between the input terminals of the ballast circuit, and the series circuit has a function of setting a value of the Z2 (xcexa9).
It is preferable that the lower limit of the resistance of the resistor is 1 Kxcexa9.
In one embodiment, the ballast circuit comprises a high frequency blocking filter including an inductance element and a capacitor, and the second capacitor is the capacitor included in the high frequency blocking filter.
In one embodiment, the discharge lamp operating apparatus further includes a lamp base, wherein the lamp base, the ballast circuit, and the discharge lamp are integrally formed.
In one embodiment, the dimmer is a dimmer for an incandescent lamp.
Another discharge lamp operating apparatus of the present invention includes a discharge lamp; a dimmer for performing phase-control with respect to an input power source; and a ballast circuit for dimming and operating the discharge lamp in accordance with an AC voltage that is phase-controlled by the dimmer. A series circuit including a capacitor and a resistor is connected between the input terminals of the ballast circuit, and the series circuit has a function of preventing ringing current that can be generated during dimming.
In one embodiment, the resistor has a resistance of 1 Kxcexa9 or more, and a relationship
Z2xe2x89xa6(Vin/Vobxe2x88x921)xc3x97Z1
is satisfied, where Z1 (xcexa9) is an impedance between an input terminal and an output terminal of the dimmer, Vob (V) is a breakover voltage of a bidirectional trigger diode that applies a trigger signal and is connected to a gate terminal of a switching element included in the dimmer, Vin (V) is an effective voltage of a commercial power source, and Z2 (xcexa9) is an input impedance between the input terminals of the ballast circuit.
A self-ballasted discharge lamp of the present invention includes a discharge lamp, a ballast circuit and a lamp base that are integrally formed. The self-ballasted discharge lamp is a lamp for dimming used in combination of a dimmer for performing phase control with respect to an input power source, the ballast circuit performs dimming and operation in accordance with an AC voltage that is phase-controlled by the dimmer, and a relationship
Z2xe2x89xa6(Vin/Vobxe2x88x921)xc3x97Z1
is satisfied, where Z1 (xcexa9) is an impedance between an input terminal and an output terminal of the dimmer, Vob (V) is a breakover voltage of a bidirectional trigger diode that applies a trigger signal and is connected to a gate terminal of a switching element included in the dimmer, Vin (V) is an effective voltage of a commercial power source, and Z2 (xcexa9) is an input impedance between the input terminals of the ballast circuit.
In one embodiment, the discharge lamp is a fluorescent lamp having a phosphor in one portion thereof. The upper limit of the Z2 (xcexa9) is 54 Kxcexa9. A series circuit including a capacitor and a resistor is connected between the input terminals of the ballast circuit, and the Z2 (xcexa9) is set by the series circuit. The lower limit of a resistance of the resistor is 1 Kxcexa9.
A dimmer of the present invention performs phase control with respect to an input power source, and supplies a phase-controlled AC voltage to a ballast circuit electrically connected to a discharge lamp. A relationship
Z2xe2x89xa6(Vin/Vobxe2x88x921)xc3x97Z1
is satisfied, where Z1 (xcexa9) is an impedance between an input terminal and an output terminal of the dimmer, Vob (V) is a breakover voltage of a bidirectional trigger diode that applies a trigger signal and is connected to a gate terminal of a switching element included in the dimmer, Vin (V) is an effective voltage of a commercial power source, and Z2 (xcexa9) is an input impedance between the input terminals of the ballast circuit.
An illumination set for dimming of the present invention includes a self-ballasted discharge lamp including a discharge lamp, a ballast circuit, and a lamp base that are integrally formed; and a dimmer combined with the self-ballasted discharge lamp. The dimmer is an external phase control apparatus for performing phase control with respect to an input power source, and supplying a phase-controlled AC voltage to the ballast circuit. The ballast circuit in the self-ballasted discharge lamp has a configuration for performing dimming and operation in accordance with the AC voltage that is phase-controlled by the dimmer, and a relationship
Z2xe2x89xa6(Vin/Vobxe2x88x921)xc3x97Z1
is satisfied, where Z1 (xcexa9) is an impedance between an input terminal and an output terminal of the dimmer, Vob (V) is a breakover voltage of a bidirectional trigger diode that applies a trigger signal and is connected to a gate terminal of a switching element included in the dimmer, Vin (V) is an effective voltage of a commercial power source, and Z2 (xcexa9) is an input impedance between the input terminals of the ballast circuit.
The present invention is configured such that the relationship
Z2xe2x89xa6(Vin/Vobxe2x88x921)xc3x97Z1
is satisfied and therefore a discharge lamp operating apparatus that can achieve a stable dimming operation from the full light state to the off-light state can be provided. Furthermore, a self-ballasted discharge lamp that is ensured of such a stable dimming operation, a dimmer used in that lamp, and an illumination set for dimming of the self-ballasted discharge lamp and the dimmer also can be provided. In addition, when a series circuit including a capacitor and a resistor is connected between the input terminals of the ballast circuit, the ringing current that can be generated during dimmer can be prevented. As a result, the dimmer can operate without malfunction due to ringing, so that a stable dimming operation from full light to off-light can be guaranteed in a comparatively simple circuit configuration.
This and other advantages of the present invention will become apparent to those skilled in the art upon reading and understanding the following detailed description with reference to the accompanying figures.